Max Keiser – journalist, former Wall Street broker and options trader, and inventor of the software which is now being used for high frequency trading – claims that the big banks retroactively allocate losing trades to their clients, and keep the winning trades for their own proprietary trading desks:

This is the second time in the couple of weeks that Keiser has made this allegation. When he first brought this up, Keiser said that he has first-hand knowledge of this unlawful activity because – when he was a trader – he and everyone else did the same thing.